Does Population Density Explain COVID-19 Death Rates in Europe?

What explains the variation in COVID-19 death rates across European countries? One factor that has been mentioned since early on in the pandemic is population density.

As a BBC article from May of 2020 states: “We know that the density of population is important for the spreading of coronavirus.” The article compares the U.K. and Italy, noting that “the U.K. is considerably more densely populated”.

And indeed, it seems plausible that the virus would spread more easily in areas where people are crammed tightly together than in areas they’re spread further apart. For example, aerosols might linger in the elevator in a multi-storey building, whereas they’re unlikely to travel between one semi-detached house and the next.

This raises the question of how to measure population density at the level of whole countries. The simplest measure is the just the number of people divided by the total land area.

However, this measure doesn’t take account of urbanisation. An ostensibly sparse country could have vast swathes of land where nobody lives. So while the average population density would be low, the majority of people might still be crammed tightly together in cities.

An alternative measure, population-weighted density, is provided by the E.U.’s Urban Data Platform. To calculate this measure for a particular country, the country is first divided into ‘parcels’ of 1km2. The population density within each parcel is computed. Then the weighted average is taken, with weights equal to the population of each parcel.

For example, suppose a country comprises ten parcels, nine of which are completely empty and one of which has a population of 100 people. The average density would be only 10/km2, but the weighted density would be 100/km2.

Using average population density, the densest country in Europe is the Netherlands. But using the UDP’s measure of weighted density, the densest country is actually Spain. (And contrary to the aforementioned BBC article, Italy is slightly denser than the U.K.) While this might seem counter-intuitive, it is consistent with other evidence.

Singaporean Ministers Announce That Country Must Learn to Live With COVID-19

Singapore has recorded fewer deaths from COVID-19 than almost any other country with reliable data: only 36 to date, which equates to a rate of just six per million. (The U.K.’s official COVID-19 death rate is 1,890 per million.)

And according to the World Mortality Dataset, Singapore has had zero excess mortality since the pandemic began. On the other hand, the country did take a sizeable economic hit last year – with GDP falling by 5.4% (compared to only 2.8% in Sweden).

What’s more, Singapore has not recorded more than 100 cases in a day since August of last year. If any advanced country has come close to “Zero Covid”, it’s Singapore.

Despite that record, three Singaporean ministers have announced that “COVID-19 may never go away” and “it is possible to live normally with it in our midst”.

Writing in The Straits Times, Gan Kim Yong, Lawrence Wong and Ong Ye Kung (the ministers for trade, finance and health) say that “COVID-19 will very likely become endemic”. This means that “the virus will continue to mutate, and thereby survive in our community”.

In other words, the Singaporean Government is under no illusion that it will be possible to eliminate COVID-19, contrary to the claims of the “Zero COVID” movement. Indeed, a survey by Nature of 119 experts found that 89% believe it is “likely” or “very likely” that SARS-CoV-2 will become an endemic virus.

“We can’t eradicate it”, the ministers write, “but we can turn the pandemic into something much less threatening, like influenza.” How do they propose to deal with the virus going forward?

First, they intend to proceed with their vaccination program, which aims to have two thirds of people vaccinated by August 9th. Second, they intend to continue testing, but “the focus will be different”. For example, the country will cease “monitoring COVID-19 infection numbers every day”. Third, they intend to keep using and developing effective treatments for COVID-19.

As Yong, Wong and Kung conclude, “History has shown that every pandemic will run its course.” Though one might object that even the few remaining measures are no longer necessary, the ministers seem to understand what they’re talking about. Their article is worth reading in full.

Excess Deaths Have Been Running Much Lower Than Official COVID-19 Deaths in Europe

Many commentators, not to mention Government spokesmen, are still relying on ‘COVID-19 deaths per million people’ as a measure of the disease’s lethality. However, we know that excess mortality – the number of deaths in excess of what you’d expect based on previous years – provides a more accurate gauge of the pandemic’s death toll.

Unlike ‘COVID-19 deaths per million people’, this measure does not vary with factors like testing infrastructure or the criteria for assigning cause of death. (Though the best measure to use is age-adjusted excess mortality.)

In the U.K. and some other countries, excess deaths ran much higher than official COVID-19 deaths in the first wave, due to a lack of testing. However, since the start of this year, they’ve have been running much lower than official COVID-19 deaths in Western Europe.

As I noted in a previous post, Ariel Kalinsky and Dmitry Kobak have collected all the available data on excess mortality in one place. (Note: they use a linear trend over the last five years as the baseline, rather than a simple average, which yields more accurate estimates of excess deaths.)

The latest version of their study includes a chart showing excess deaths and official COVID-19 deaths over time in sixteen different countries:

In Peru, Mexico and South Africa, excess deaths have been running substantially higher than official COVID-19 deaths since the start of the pandemic. By contrast, in all but four of the European countries, excess deaths closely matched official COVID-19 deaths up the end of 2020.

However, since the beginning of 2021, excess deaths have been running lower – often much lower – than official COVID-19 deaths in every European country. In Austria, Belgium, Germany, the Netherlands, Sweden, Switzerland and the U.K., excess deaths have been negative (i.e., below the baseline) for multiple consecutive weeks. 

Some of these disparities could be due to reporting delays for all-cause deaths. However, the authors “excluded the most recent data points whenever there was an indication that the data were substantially incomplete”, so such delays are unlikely to be a big contributor. And in any case, the largest disparities between excess and official deaths are not seen in the most recent weeks. 

Overall, Kalinsky and Kobak’s findings indicate that excess deaths has become untethered from official COVID-19 deaths in Europe, and the latter measure is now substantially overstating the pandemic’s death toll. 

UK No Longer Has Highest Covid Death Rate in the World

Remember those headlines saying the UK had the highest number of Covid deaths in the world? Back in January, Sky News reported the UK’s daily Covid death toll was the highest in the world. Some news services went further, saying the UK had the highest number of Covid deaths per capita in the world. But new data published by Statista shows that, in fact, the UK’s deaths-per-million are the sixth-highest in the world.

Some small crumbs of comfort there for the Government.

Worth reading in full.